How big of a deal is getting a paper published as an undergrad?

I have submitted a publication to
physics Letters A in the field of supersymmetric quantum mechanics (SUSYQM)

my teacher says this is a pretty big deal but would like to hear some others opinion. I will obviously mention this when I apply but is it THAT big of a deal? Should I make a big deal about it when I apply? How much will it help me? I have some dumpy math grades from my sophomore year so I am worried about getting into a good school. What should I make of it?

I am only an undergrad myself, but by what I have heard, having a publication on your record is very beneficial since it shows that you have had quality research experience. This is important to graduate programs since they expect their graduate students to be active researchers. It will definitely look great on your resume, but (by my limited experience) it is not anywhere near essential.

saying that it is, how should I use it? WIll it speak for itself? How should I handle it? I am trying to get a feel for what position this puts me in, I am very concerned about some very bad math grades in my soph. year.